A clutch is a mechanical device that engages and disengages the power transmission, especially from a driving shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts.
Coiled tubing units employ clutches for operating a levelwind system in conjunction with the coiled tubing reel to guide coiled tubing onto the reel when the coiled tubing is removed from an oil or gas well and to guide the coiled tubing from the reel when the coiled tubing is injected into an oil or gas well is disclosed. Drive means are provided for rotating the coiled tubing reel and the levelwind system. The levelwind system uses a levelwind screw between two levelwind arms to move a tubing guide laterally across the coiled tubing reel in order to properly wrap and unwrap the tubing from the reel. The screw is turned at a rate proportional to the rate of reel rotation in order that the tubing guide may move at approximately the rate of the current wrap position. The levelwind system further employs the clutch to adjust the positioning of the tubing guide laterally along the levelwind screw and maintain the straightest path for the tubing from the reel through the tubing guide during spooling and un-spooling operations. Misalignment of the tubing between the reel and the tubing guide may exert undue forces and wear on equipment and inhibits deployment or retrieval speed.
Current “friction” clutches used today employ discs that perpetually wear against each other and must be replaced frequently. Inevitably, no matter the hardness of the material, the discs will wear through and break and often they last through only a few jobs before the coiled tubing unit must be taken out of service and the discs replaced. To avoid spare part expenses and maintenance downtime, some operators have even disabled the clutch, but this practice is not recommended due to the inability to control the spooling/un-spooling, without continuous operator engagement. Friction clutches also inhibit spooling new tubing onto the reel for the first time. The tubing yard uses a machine to spool new tubing on the reel, which is done with the clutch free to rotate. To allow the clutch to rotate freely, drive chains to the clutch must be removed which increases the possibility of assembly error on these components due to installation and removal frequency. What is needed then is an improved clutch mechanism.
In one aspect, embodiments disclosed herein relate to a clutch mechanism for use with a levelwind screw of a coiled tubing reel configured to guide coiled tubing onto or from a coiled tubing reel driven by a reel motor, the clutch mechanism including a meshing arrangement between a first component coupled to the levelwind screw and a second component driven by the reel motor.
In another aspect, embodiments disclosed herein relate to a method of operating a levelwind screw of a coiled tubing unit using a clutch mechanism comprising a meshing arrangement between a first component coupled to the levelwind screw and a second component driven by a reel motor. The method includes engaging the meshing arrangement and rotating the coiled tubing reel, thereby operating the levelwind screw, or disengaging the meshing arrangement and rotating the levelwind screw.
In yet another aspect, embodiments disclosed herein relate to a clutch mechanism including a meshing arrangement between a first plurality of teeth on a first component coupled to a driven shaft and a corresponding second plurality of teeth on a second component coupled to a driving shaft.
In yet another aspect, embodiments disclosed herein relate to a method of operating a levelwind screw of a coiled tubing unit using a clutch mechanism, the method including meshing a first plurality of teeth of a first component coupled to the levelwind screw with a corresponding second plurality of teeth of a second component driven by a reel motor, and operating the reel motor to rotate the coiled tubing reel, or unmeshing the first plurality of teeth from the corresponding second plurality of teeth, and rotating the levelwind screw.